It is already known to the person skilled in the art that foamed polymeric materials may be created from a variety of processes including but not limited to thermo setting, thermo plastic and other similar techniques which simply involve the expansion of a particular thermo plastic polymer or at least a formation of polymers with the assistance of a blowing agent.
For example, polystyrene is a well recognised polymer derived from individual monomer units of styrene which is extracted from liquid hydrocarbon obtainable from petroleum.
The most common form of polystyrene is generally expanded polystyrene (EPS) but products from polystyrene are also made from extruded treated polystyrene of which will be further introduced below.
It is long known that in the trade that expanded polystyrene is manufactured through the introduction of a gaseous blowing agent of around about 5% into 95% polystyrene by weight, preferably pentane or carbon dioxide. With the application of heat, solid plastic is expanded into foam. Generally the heat is introduced to initialize the polymerisation through steam above 95 degrees Celsius.
Extruded polystyrene (EPS) on the other hand, is formed under high pressure and temperatures to avoid generating a gas which would bring about an expansion as is the case with EPS.
The benefits of solid foam polystyrene whether created by an extrusion or an expansion process is that what is provided for is a material having particular useful characteristics in that the voids containing trapped air provides suitability as a building material for use in structural insulation and the like. Nonetheless polystyrene and the products made there-from are characterised as being highly flammable or at least easily ignitable.
Consequently, though such products are efficient insulators at low temperatures, it is not possible for such materials to be used in any exposed installations in buildings or elsewhere. In many places, the building codes and relevant laws and regulations stipulate that polystyrene products and material must be concealed behind dry wall, sheet metal or concrete.
As the person skilled in the art would appreciate, if material made of polystyrene was placed in situations where temperatures increased, for example exposure to an open plain, these foam plastic materials would easily become accidentally ignited, bringing about extensive fire damage.
Due to the fire hazards associated with polystyrene material and the products derived there-from, another polymeric material known as polyurethane, which can also form various types of foams to form a variety of products is used in its place.
Nonetheless as will be introduced shortly below, whether it is polyurethane, polystyrene, latex, paints, glues or any other polymeric material, all such products are essential flammable and their use in general purpose applications is often not permissible because of the presented hazards that potentially can occur.
Polyurethane is made up of organic units joined by urethane links. Its uses are diverse and for polyurethane form to foam, because it can be presented in various flexible and rigid types it makes it suitable to be used with upholstery fabrics in commercial and domestic furniture, whereas the more rigid foams are applied to the insides of metal and plastic walls as one would see on fringes and the like, and applications where thermal insulation panels in a building arrangement would be required.
Still further, it is well recognised in the trade that expanding polyurethane foams, as it can be presented in a variety of forms, makes not only useful for insulation, but there are also further applications in packaging, sound deadening devices, flotation, upholstery Madding, varnishing, glues, furniture manufacturing, sealants and even electronic components.
Polyurethane products are normally manufactured by a reaction of polyisocyanante and a polyol, for example such that those having an organic structure with at least two isocyanate or alkali groups, in the presence of a blowing agent and also a catalyst will assist the rate of reaction.
It is these polyols and plastics that then form the basis of so many products of which are referred to above and are used throughout industry.
The light polystyrene derived products polyurethane, is also well known for presenting a real risk of fire hazards because of its foam-ability.
The cell structure of these foaming polymeric products, particularly those of high organic content and large surface area will decompose and burn rapidly when exposed to fire and/or high temperatures.
Once ignition of the fire has taken place the problem worsens because as the polymeric material begins to drip, it serves to spread to fire, omitting large quantities of smoke and also toxic gases that were contained within the foam material.
As the person skilled in the art would appreciate one mechanism in order to solve the problem of flammable polymeric material would be to protect the foam plastic material with some type of fire retarding arrangement.
As explained in U.S. Pat. No. 4,551,483, polymeric foams characterised for being included in products such as mattresses, upholstered furniture, building materials, vehicle installation and seating, housing interiors, electrical equipment and the like. Nonetheless when burning, it produces toxic gases.
The product is still used however because of its resilient characteristics and because it can be moulded to the shapes required. It would be however, advantageous as stated to make the foam fire retardant.
As further explained in U.S. Pat. No. 4,551,483, foam shapes are moulded by using a two part mould which when closed, form a cavity of the desired shape and into one of which are just blended polymeric material, normally comprising of polyol is blended with a catalyst, is poured and the other mould parties quickly close on the first part to form the cavity. The amount of blend is proportional to only partly filled the cavity prior to foaming.
Polymeric material foams quickly and fills the mould cavity, after which the mould is open and the moulded shape is removed.
As stated in the document methods of applying a fire retardant to such polymeric foams' shapes are ineffective. For other materials it is known that various dry fire retardant substances can be ground and incorporated with water and applied by painting, spraying and the like with some effectiveness.
Nonetheless one important problem as stated has been that such fire retardants include active components which are essential volatile so if applied to the surface of the foam, their effectiveness after drying is also short lived.
These arrangements generally have the fire retardant substances as finely powdered and blended dry directly into the polyol of the polyurethane blend prior to its foaming by blending in the catalyst, they are distributed during foaming throughout the foam as fine particles which are encapsulated by the polyurethane so as to protect them from evaporation after foaming is completed.
Protection against being worn away as is in the case of a surfactant application, is also provided. The fire retardant particles remain substantially unchanged until released by initial burning of the foam, at which time they become effective as a fire retardant.
Applying such an arrangement has been effective using fire retardants, such as ammonium phosphate, ammonium chloride, sodium bicarbonate and borax.
As the person skilled in the art has been taught such effective fire retardants blended into the polymeric material are mixed and before or after mixing are finally ground.
However, the problem with using these fire retardants which have been grounded up and powdered and incorporated into the polymeric material is that all of the fire retardants would not be considered environmentally friendly, and still further, all such fire retardant mixes described above and considered effective could not be considered harmless fire retardants as each contain protein based material.
As the person skilled in the art would appreciate, protein leads to allergic reactions potentially on the skin of users, and therefore compositions including such ingredients could not be classified as harmless.
Still further, a fire retardant that contains protein such as ammonium phosphate and urea, which as introduced above was considered an effective fire retardant following incorporation into polymeric material during the foaming stage, is that once the retardant comes in contact with water, it then re-enters environments which these proteins can be fed off leading to various environmental hazards.
Therefore there still remains a need in the relevant art to allow polymeric material such as polystyrene and polyurethane to be applied to its widespread industrial applications, without a fire hazard, this same consideration also extends to other flammable polymeric material such as rubber, varnishes, paints, glues.
However the more particular problem is not only is there a need to provide fire retardant suitability to such material, but the fire retardant characteristic to be introduced into the intermediate and then into the final product to which that material will be applied to, should be such that itself is also harmless and environmentally friendly.
In Patent Number PCT/AU03/00980 there is provided for a harmless fire retardant protein free composition. As described in Patent Number PCT/AU03/00980 the introduction of the tetra potassium pyro phosphate provided for a harmless fire retardant that had a double action when combating a fire hazard situation.
Advantageously, the composition containing tetra potassium pyro phosphate was able to absorb the heat from the article being treated for flame attack, and therefore able to cool the area around the flame, and at the same time being able to consume any free oxygen which may be fuelling the fire.
Hence the composition of the fire retardant described in Patent Number PCT/AU03/00980 had an almost dual type simultaneous action working on the fire, not only to cool the product, making it less susceptible to further ignition by fire, but also to scavenge any oxygen in the vicinity of the flame to which would fuel such a flame.
Nonetheless such a described harmless fire retardant protein free composition because of the conditions of manufacturing many polymeric materials such as polyurethane and polystyrene referred to today would be, that in the case of polystyrene, the high temperatures would destroy the aqueous conditions presented in the harmless fire retardant protein free composition thereby deactivating the ability for the fire retardant to act subsequently when called upon.
Still further, in the case of polyurethane manufacture, the actual aqueous content of the harmless fire retardant protein free composition could influence the controlling cell structure of the foams being created, as some of the composition itself becomes involved in the reaction between the polyol and the isocyanate groups.
Nonetheless the harmless fire retardant provided for in PCT/AU2003/00980 was designed for the most part to be a prophylactic surface treatment application, primarily with focus on cellulose materials and other natural organic fibre material applications.
Therefore there remains a need to come up with an improved more flexible harmless fire retardant to the one provided for in PCT/AU2003/00980 so it can be more universally applied to a wide range of products and applications.
The object of this invention is to provide a method for producing an all purpose harmless fire retardant protein free composition that is flexible enough to have the ingredients of the composition adjusted in quantity, kind and physical structure so as to have the composition adaptable to be incorporated into a range of differing material, of which material forms an intermediate or finished product requiring fire retardant characteristics.